Prior to committing to an action, it would be helpful to know how long to expect that action to take, and since this is often related to the size of the files, this information should be accessible by those not already familiar with the files. Larger files will clearly take longer to act upon, so an expectation would be set with this information. Ideally this could be used to drive an estimate of how long the action will take, but that would introduce additional variables, so total file size would be a good start.
